Arcuate seed casting method

Abstract

A casting method includes forming a seed. The seed has a first end and a second end and an inner diameter (ID) surface and an outer diameter (OD) surface. The seed second end is placed in contact or spaced facing relation with a chill plate. The first end is contacted with molten material. The molten material is cooled and solidified so that a crystalline structure of the seed propagates into the solidifying material. At least a portion of the seed contacted with the molten material has a solidus higher than a solidus of at least an initial pour portion of the molten material.

What is claimed is: 
     
       1. A casting method comprising:
 forming a seed, the seed having a first end and a second end and an inner diameter (ID) surface and an outer diameter (OD) surface; 
 placing the seed second end in contact or spaced facing relation with a chill plate; 
 contacting the first end with molten material; and 
 cooling and solidifying the molten material so that a crystalline structure of the seed propagates into the solidifying material, 
 
       wherein:
 at least a portion of the seed contacted with the molten material has a solidus higher than a solidus of at least an initial pour portion of the molten material; 
 a subsequent pour portion of the molten material has a solidus higher than the solidus of the initial pour portion; and 
 after the solidifying, the initial pour portion and remainder of the seed are removed from the subsequent pour portion. 
 
     
     
       2. The method of  claim 1  wherein:
 the solidus of the initial pour portion is lower than a solution temperature of said portion of the seed. 
 
     
     
       3. The method of  claim 2  wherein:
 the solidus of the initial pour portion is at least 25° C. lower than the solution temperature of said portion of the seed. 
 
     
     
       4. The method of  claim 3  wherein:
 the solidus of said portion of the seed is at least 25° C. higher than the solidus of the initial pour portion. 
 
     
     
       5. The method of  claim 1  wherein:
 the solidus of said portion of the seed is at least 25° C. higher than the solidus of the initial pour portion. 
 
     
     
       6. The method of  claim 1  wherein:
 the solidus of said portion of the seed is 25° C. to 200° C. higher than the solidus of the initial pour portion. 
 
     
     
       7. The method of  claim 1  wherein:
 the seed and the molten material are nickel-based superalloys. 
 
     
     
       8. The method of  claim 1  wherein:
 the solidus of the subsequent pour portion of the molten material is 25° C. to 200° C. higher than the solidus of the initial pour portion. 
 
     
     
       9. The method of  claim 1  wherein:
 the molten material solidifies as a full annulus component. 
 
     
     
       10. The method of  claim 1  wherein:
 the seed is a single crystal seed. 
 
     
     
       11. The method of  claim 10  wherein:
 the forming comprises bending. 
 
     
     
       12. The method of  claim 11  wherein:
 the solidus of said portion of the seed is at least 25° C. higher than the solidus of the initial pour portion. 
 
     
     
       13. The method of  claim 12  wherein:
 the molten material solidifies as a full annulus component. 
 
     
     
       14. The method of  claim 1  wherein:
 the forming comprises bending. 
 
     
     
       15. The method of  claim 14  wherein:
 the solidus of said portion of the seed is at least 25° C. higher than the solidus of the initial pour portion. 
 
     
     
       16. The method of  claim 15  wherein:
 the removing essentially leaves only the second pour portion. 
 
     
     
       17. The method of  claim 16  wherein:
 the molten material solidifies as a full annulus component.